The confirmation debate over Neal Gorsuch’s nomination to the Supreme Court has turned into bitter battle between the two parties, but the violence within the Republican Senate caucus might be even worse.

The only way Republicans will be able to confirm Gorsuch is by voting to pass the infamous “nuclear option,” a change to the Senate rules that would effectively mean Supreme Court nominees could not be filibustered and could be confirmed by 51 votes instead of 60.

The Senate has been at the brink of “nuclear” before and backed down. But the current Senate Majority Leader, Mitch McConnell, said this week that passing the nuclear option would be good for the Senate and the system.

“Look at the Senate through the long history of the body, the practical effect of all this will be to take us back to where we were,” McConnell said.

That drew a full roar from another Republican lion of the Senate, Sen. John McCain, R-Ariz.

“Idiot, whoever says that is a stupid idiot, who has not been here and seen what I’ve been through and how we were able to avoid that on several occasions,” McCain said Wednesday. “And they are stupid and they’ve deceived their voters because they are so stupid.”

Trent Lott, the former leader of Senate Republicans, gave the rules change the nickname “nuclear option” years ago because he thought the fallout would be so toxic. It seems he was right.

McConnell laughed off McCain’s insult, chuckling, “I don’t think I have any comment on that.”

McConnell can afford to have the last laugh. He has the votes to pass the nuclear option, including McCain’s.